These days information products are widely used in the society. Adapters are commonly adopted to mate various electronic products to provide stable electric power. The conventional adapter includes an input end and an output end, such as one disclosed in R.O.C. patent No. 529822 entitled “Adapter equipped with a power indication light” The adapter is made at a size and shape to make carrying easier to be sold or carried with electronic products. It also has a power cord at one end that can be bundled to facilitate storing. However, wire storage often is a problem on the general adapter. To resolve the problem of wire storage, R.O.C. patent No. M350899 entitled “Adapter equipped with unit winding” proposes a structure in which a wire winder (winding disc, helical spring or the like) is provided between an upper cover and a lower cover of the adapter in addition to circuit elements to retract the conducting wire of the adapter. While the adapter with the wire winder thus formed can keep the exterior neat and tidy, and also provide wire winding function, the interior space is limited and a cooling space is needed. The wire winder hinders air circulation inside and cooling capability of the adapter suffers. Moreover, the adapter with greater power contains more voluminous circuit elements and requires larger insulation space. Hence having a built-in wire winder in a large power adapter is not advisable.
In order to free the wire winder from occupying the interior space of the adapter, other techniques installing the wire winder outside the adapter have been proposed. For instance, R.O.C. patent No. M299946 entitled “Concealable and extensible adapter plug structure” discloses an adapter containing a concealable and extensible plug, and also including a wire winder to wind a conducting wire at another end of the adapter. Although the wire winder is located outside the adapter without occupying the interior space needed for cooling and holding circuit elements, there is no holding place to hold and fix the wire winder. The wire winder is dangling and entangling outside the adapter and creates a lot of annoyance and trouble to users. Hence there are still rooms for improvement.